Electromagnetic hammer



Jan. 2, 1934.

G. M. J. BLOMQVIST Er AL 1,941,655

ELECTROMAGNETIC HAMMER Filed Jan. 18, 1929 fig 1/ (ll/V by I'T Ill 1 'rlllll ATTORNEYS Patented Jan. 2, 1934 1 UNITED STATES ELECTROMAGNETIC HAMMER Gustav Marten Justinus Blomqvist and Frans Oscar Johansson Kinley, Stockholm, Sweden Application January-18, 1929, Serial No. 333,316, and in Sweden September 23, 1926 9 Claims.

Electromagnetic hammers, consisting of solenoids i. e. two or several windings and an iron core or spindle moving to and fro through these solenoids and working upon a cutting chisel, are

; previously known.

The present invention relates to electromagnetic hammers consisting of one or several electromagnets, i. e. windings on fixed iron cores in which the magnetic lines of force may be con- 10 centrated and of an iron spindle moving to and fro. These hammers being supposed to be held by hand during operation are subjected to forcible vibrations, which may cause a derangement of the current interrupter device if mechanically connected to the hammer.

The present invention provides a hammer in which said device is mechanically separated and conveniently disposed remotely from the hammer the latter being connected with the interrupter device exclusively through electrical conductors.

By designing the iron cores of the electromagnets with a circular shape and the armature in the shape of a plate, practically the entire electromagnetic flux is forced to pass through the iron cores and the armature as shown on the drawing. In case alternating current is used the iron cores should be divided into thin sheets.

- Such a core may be composed of an iron sheet spindle insulated with paper.

Further considerable power losses occur in the hammer as the spindle or that part which transfers the reciprocating motion of the armature to the cutting chisel is passing through the magnetic field. This appears as a restraining effect upon 5 the movement of the spindle and the armature.

The same result is obtained also if the cutting chisel itself is extended through the yoke, the spindle then being kept away from the magnetic field. The material in this spindle is thus of vital importance for the functioning of the apparatus and only the very best steel is fit for use owing to the considerable strains occurring in operation. When ordinary steel is used, the

above mentioned power losses are unavoidable for which reason the spindle is made of a material that is non-magnetic or nearly non-magnetic at normal temperature and yet of good resistance, for instance austenitic manganeseor nickel-steel.

The invention will now be described in detail with reference to the accompanying drawing showing an embodiment of a hammer-reciprocat ing motor system.

Fig. 1 is a longitudinal cross-sectional detail of one embodiment of the invention;

Fig. 2 is a transverse cross-sectional view of another embodiment; and

Fig. 3 is a longitudinal sectional detail of this other embodiment.

The hammer shown in Fig. 1 is provided with two electromagnets a1, a2, and two electromagnets b1, D2, of which the two former and the two latter are in combination and are alternately energized and thus attract the armatures c in opposite directions. The electromagnets are preferably of the so-called pot type in which the cylindrical coil is inserted in the space between an outer magnet shell and an inner tubular core coaxial therewith. Through the bore of the inner core the spindle d is passed. The free ends of said shell and said core face the space in which the armature c is movable whereas their opposite ends are magnetically united. The armatures operate the cutting chisel e by means of the common spindle d. The alternating energization of the electromagnets is brought about by the interrupter or switch device, shown below to the left of the hammer.

This switch device consists principally of a two-way switch operated by two electromagnets so a and 1), between which the armature 0 may reciprocate. The switch armature is fixed upon the spindle d1, on which also an insulated contact (21 is fixed. When the armature is moving to and fro between the electromagnets, the con- 35 tact e1 is moving between the fixed branch contacts f1 and f2, and thus alternately interrupting the current supply from the positive pole through the two electromagnet circuits of the hammer and further through one of the switch electromagnet circuits. It appears from the diagram that this is going on alternately. hi and k2 are two condensers connected between the point g and the both contacts f1 and 12, in order to counteract sparking at the interruptions between f1 or is respectively and e. The space between f1 and f2 may also be filled out with a hard insulating mass as for instance potstone. The ends of the contact e are to be insulated with a similar mass in order to prevent sparking between the contacts h or f2 respectively and e' there being no airgap for a possible spark between these contacts.

The sysiem operates as follows: In the position shown in Fig. 1 the contact :21 receives positive potential and current flows through the stationary contact f1, one of the conductors to the hammer, the two hammer coils a1 and as in parallel, back through a conductor to the switch de vice. through the switch coil b, and to the negative pole. Accordingly, the hammer armature c is retracted upwards whereas the switch armature 01 is pulled to the right thereby shifting the contacts. Upon completed shifting the contact f2 will, instead of f1, receive positive potential.

The coils a1 and as are now deenergized and the mutually parallel-comiected hammer-impacting coils in and b2 are energized. Further the coil 1) is deenergized and the coil a energized. The armature c is forced to strike downwards whereas, at the same time, the coil it attracts the armature 01 to the left into the position illustrated and the same cycle of operation will be repeated once more and so on.

In the embodiment shown in Figs. 2 and 3 there are provided two hammer impacting coils b3 andb4 as in the embodiment in Fig. 1 but only one hammer retracting coil as, it being understood that the impacting impulse should be greater than the retracting impulse.

The interrupter device may of course be carried out in different ways and is not limited to the embodiment shown in the drawing.

We claim:

1. A hammer-reciprocating motor system, comprising a hammer-reciprocating armature, two hammer-electromagnets for the alternate attraction of said hammer armature in opposite directions, two separate electric current paths for the alternate energization of said hammer-electromagnets, a remote two-way switch, a switch reciprocating armature, two switch actuating'coils for the alternateattraction of said'switch armature in opposite directions, a source of current connected to a common contact of the two-way switch and to common terminals of the-switch actuating coils, and two separate series circuits from the other terminals of these coils to the branch contacts of the two-way switch, each circuit permanently including one of the hammer current paths.

2. A hammer-reciprocating motor system, comprising a disc-shaped, hammer-reciprocating armature, two hammer-electromagnets for the alternate attraction of said hammer armature in opposite directions, two separate electric current paths for the alternate energization of said hammer-electromagnets, a remote two-way switch, a switch reciprocating armature, two switch actuating coils for the alternate attraction of said switch armature in opposite directions, a source of current connected to a common contact of the two-way switch and to common terminals of the switch actuating coils, and two separate series circuits from the other terminals of these coils to the branch contacts of the two-way-switch, each circuit permanently including one of the hammer current paths.

3. A hammer-reciprocating motor system, comprising a hammer-reciprocating armature comprising a non-magnetic core supporting spaced apart discs of magnetic material, hammer-electromagnets for the attraction of said hammer armature alternately in opposite directions, two mutually insulated electric current paths for the alternate energization of said hammer electromagnets, a remote two-way switch, a switch recipr'ocating armature, two switch actuating coils for the alternate attraction of said switch armature in opposite directionspa source of current connected to a common contact of the two-way switch and to common terminals of the switch actuating coils, and two separate series circuits from the other terminals of these coils to the branch contacts of the two-way switch, each circuit permanently including one of the hammer current paths.

4. A hammer-reciprocating motor system, comprising a hammer-reciprocating armature comprising a non-magnetic core supporting spaced apart discs of magnetic material, two hammerimpacting magnet coils and one hammer retracting magnet coil for the alternate attraction of said hammer armatures in opposite directions, a remote two-way switch, a switch reciprocating armature, two switch actuating magnet coils for the alternate attraction of said switch armature in opposite directions, and a source of current connected to a common contact of the two-way switch and to common terminals of the switch actuating coils, and two separate series circuits from the other terminals of these coils to the branch contacts of the two-way switch, one circuit including the two hammer impacting coils, and the other circuit the retracting coil.

5. A hammer-reciprocating motor system, comprising a hammer-reciprocating armature comprising a non-magnetic core supporting spaced apart discs of magnetic material, two hammer impacting magnet coils and two hammer retracting magnet coils for the alternate attraction or said hammer armature in opposite directions, a remote two-way switch, a switch reciprocating armature, two switch actuating magnet coils for the alternate attraction of said switch armature in opposite directions, and a source of current connected'to a common contact of the two-way switch and to common terminals of the switch actuating coils, and two separate series circuits from the other terminals of these coils to the branch contacts of the two-way switch, one circuit including the two hammer impacting coils, and the other circuit the retracting coils.

6. A hammer-reciprocating motor system, comprising a hammer reciprocating armature comprising a non-magnetic spindle supporting spaced apart discs of magnetic material, two hammer impacting magnet coils and one hammer retracting magnet coil for the alternate attraction of said hammer armature in Opposite directions, a remote two-way switch, a switch reciprocating armature, .two switch actuating magnet coils for the alternate attraction of said switch armature in opposite directions and a source oi. current connected to a common contact of the two-way switch and to common terminals of the switch actuating coils, and two separate series circuits from the other terminals of these coils to the branch contacts of the two-way switch, one circuit including the two hammer impacting coils, and the other circuit the retracting coil.

'7. A hammer-reciprocating motor system, comprising a hammer reciprocating armature comprising a non-magnetic spindle supporting spaced apart discs of magnetic material, two hammer impacting magnet coils and two hammer retracting magnet coils for the alternate attraction oi! said hammer armature in opposite directions, a remote two-way switch, a switch reciprocating armature, two switch actuating magnet coils for the alternate attraction of said'switch armature in opposite directions and a source of current connected to a common contact of the two-way switch and to common terminals of the switch actuating coils, and two separate series circuits from the other terminals of these coils to the branch contacts of the two-way switch, one circuit including the two hammer impacting coils, and the other circuit the retracting coils.

8. A hammer-reciprocating motor system, comprising a hammer reciprocating armature comprising a non-magnetic core supporting spaced apart discs of magnetic material, two mutaully parallel-connected hammer impacting magnet coils and one hammer retracting magnet coil for the alternate attraction of said hammer armature in opposite directions, a remote two-way switch, a switch reciprocating armature, two switch actuating magnet coils for the alternate attraction of said switch armature in oppositedirections, and a source of current connected to a common contact of the two-way switch and to common terminals of the switch actuating coils, and two separate series circuits from the other terminals of these coils to the branch contacts of the twoway switch, one circuit including the two hammer impacting coils, and the other circuit the retracting coil.

9. A hammer-reciprocating motor system, comprising a hammer reciprocating armature comprising a non-magnetic core supporting spaced apart discs of magnetic material, two mutually parallel-connected hammer-impacting magnet coils, and two mutually parallel-connected hammer retracting magnet coils for the alternate attraction of said hammer armature in opposite directions, a remote two-way switch, a switch reciprocating armature, two switch actuating magnet coils for the alternate attraction of said switch armature in opposite directions, and a source of current connected to a common contact of the two-way switch and to common terminals of the switch actuating coils, and two separate series circuits from the other terminals of these coils to the branch contacts of the twoway switch, one circuit including the two hammer impacting coils, and the other circuit the retracting coils.

GUSTAV MARTEN JUSTINUS BLOMQVIST. FRANS OSCAR JOHANSSON KIN'LEY. 

